This invention relates to precision mechanical positioning apparatus with particular application in translating physical position into an electronic format.
Encoders of various configurations have been utilized to translate information from the physical world to the electronic format required for calculation and further processing. These "sensors" have wide applicability in moving machinery and in rotating machinery in particular. Servo mechanisms, such as used in robotics and other industrical applications, have particular need for precise locating sensors which can reliably and quickly provide an input to a digital or analog control system to provide feedback knowledge with respect to current position. Thereafter, rate of change of that position as velocity is readily determined when required. Typically, an aperture is provided in a moving shutter plate which will allow light to pass between a light source and an optically sensitive sensor which will indicate the position when the aperture is properly positioned therebetween. This basic configuration has limitations in the numbers of sensors as well as the size and placement of apertures in the rotating shutterplate. Furthermore, to obtain improved resolution, a direct function is related between the numbers of apertures and sensor tracks and the resolution capability.